ocd explanation

• genetic explanations?

  the comt gene, the sert gene, diathesis-stress
• what is the comt gene?

  it is involved in the production of catechol-o-methyltransferase, regulates the production of dopamine, one form is more common in ocd patients
• what is the sert gene?

  affects the transport of serotonin, lower levels of which are implicated in ocd, one study found a mutation of this gene in two unrelated families where six of the seven family members had ocd
• what is diathesis-stress?

  the idea of a simple link between one gene and a complex disorder is unlikely, genes like the sert gene are also implicated in a number of other disorders such as depression and ptsd, what this suggests is that each gene only creates vulnerability and other factors affect what condition develops
• neural explanations?

  abnormal levels of neurotransmitters, abnormal brain circuits
• what is abnormal levels of neurotransmitters?

  dopamine levels are thought to be abnormally high in people with ocd while lower levels of serotonin are associated with ocd
• what are abnormal brain circuits?

  several areas in the frontal lobes are thought to be abnormal in people with ocd. this is supported by pet scans of patients with ocd taken while their symptoms are active. such scans show heightened activity in the orbitofrontal cortex. serotonin and dopamine are linked to these regions of the frontal lobes. high levels of dopamine also lead to overactivity in the basal ganglia
• abnormal frontal lobe areas in people with ocd?

  the caudate nucleus (located in the basal ganglia) normally suppresses signals from the orbitofrontal cortex. in turn, the orbitofrontal cortex sends signals to the thalamus about things that are worrying. when the caudate nucleus is damaged, it fails to suppress minor worry signals and the thalamus is alerted
• what is concordance rate?

  a measure of genetic similarity
• what is dopamine?

  one of the key neurotransmitters in the brain, with effects on motivation and ‘drive’
• what is a gene?

  a part of the chromosome of an organism that carries information in the form of dna
• what are neurotransmitters?

  chemical substances that play an important part in the workings of the nervous system by transmitting nerve impulses across a synapse